In a conventional beverage container such as a beer barrel, a ferrule is fixed to the beverage container by welding or the like, and a fitting is attached to the ferrule by screwing. A dispensing head is then connected to the fitting. Pressurized gas such as carbon dioxide is supplied to the beverage container through the dispensing head, and thus the beverage in the beverage container is dispensed to the exterior of the container. The manner in which a conventional fitting is attached to a ferrule will now be described with reference to FIGS. 25 and 26.
FIG. 25 is a sectional view showing the manner in which a conventional fitting is attached to a beverage container from the front. FIG. 26 is an enlarged sectional view showing a part of the fitting and the ferrule. FIG. 25 shows a case in which the beverage is draft beer and the beverage container is a beer barrel. An attachment member 2 of the fitting is screwed fixedly to the inside of a ferrule 91 provided on an upper portion of a beer barrel 9. Further, a down tube 5 biased upward by a spring is attached to the attachment member 2.
A gas valve 3 is fixed to an upper end portion of the down tube 5, and a beer valve 4 is provided in the interior of the upper end of the down tube 5 so as to be biased upward. The gas valve 3 and beer valve 4 are set in a closed state by the biasing force of a coil spring. A dispensing head may be attached to the ferrule 91 and the attachment member 2. The attachment member 2 and dispensing head can be joined easily by a connecting mechanism constituted by an engaging protrusion 22 and an engaging recess portion.
The dispensing head is a device for manipulating the gas valve 3 and beer valve 4 such that a pressurized gas such as carbon dioxide gas is supplied to the interior of the beer barrel 9, thereby raising the internal pressure of the beer barrel 9 such that the draft beer is dispensed to the exterior of the container. The draft beer is dispensed to the exterior of the container through the down tube 5 and the beer valve 4. To prevent gas leakage between the ferrule 91 and the attachment member 2, packing 92 is provided between a lower portion inner surface of the ferrule 91 and the attachment member 2.
A shooting prevention member 8 prevents the attachment member 2 from being shot upward by the internal gas pressure of the beer barrel 9 when the attachment member 2 is detached from the ferrule 91. A stopper 81 contacts the lower surface of the ferrule 91, thereby preventing the ferrule 91 from shooting upward. When the gas valve 3 is pushed down by a detachment tool, pressurized gas escapes from the interior of the beer barrel 9 and the stopper 81 is pulled inward, and thus the attachment member 2 can be detached from the ferrule 91.
Although the attachment member 2 is screwed fixedly to the ferrule 91 in the fitting constituted in this manner, a minute gap exists between the ferrule 91 and the attachment member 2. Rainwater and draft beer enter through this gap. This dirty water that enters through the gap is prevented from infiltrating the interior of the beer barrel 9 by the packing 92 but in terms of hygiene, it is not desirable for the dirty water to remain between the ferrule 91 and attachment member 2 for a long time. When the beer barrel is washed and sterilized at a high temperature, the dirty water in the gap is ejected through ebullition, and therefore it is possible to check whether or not any dirty water remains in the gap. The dirty water in the gap may seep out through the gap due to thermal expansion when the beer barrel is placed under hot sunlight or the like, and may also infiltrate the interior of the ferrule, thereby contaminating the draft beer.
Hence, the inventor of the present application has proposed the fitting described in Patent Document 1. In the fitting of Patent Document 1, a second sealing member is provided on an uppermost portion of the fitting in addition to a first sealing member for sealing the gap between the lower portion inner surface of the ferrule and the attachment member, thereby making it difficult for foreign matter, rainwater and so on to enter through the gap between the ferrule and the attachment member.    Patent Document 1 Japanese Unexamined Patent Application Publication 2000-79991